1. Field of the Invention
This invention relates to a holder for pre-filled cartridge-needle units.
2. Description of the Prior Art
Disposable medicament-containing cartridge needle units for use in conjunction with reusable hypodermic syringe holders are well known in the art and are in widespread commercial use such cartridges conventionally feature a cylindrical body closed at the proximal end with a flexible plunger slidable within the bore of the cartridge and closed at the distal necked-down end with a septum secured to the cartridge by a crimped-on aluminum collar. The necked-down distal end conventionally is fitted with a needle hub/needle/needle guard assembly. Such cartridge-needle units are available from Sanofi Winthrop Pharmaceuticals under the Carpuject.RTM. trademark.
In use, the cartridge-needle unit must be activated, i.e., the proximal end of the needle cannula must penetrate the sealed septum such that communication is achieved between the fluid and the proximal end of the needle. Some cartridge-needle units are sold in an activated form. Others must be activated by the user. When user activated cartridge-needle units are used in conjunction with conventional reusable syringe holders of the type described, for example, in Hadtke, U.S. Pat. 4,585,445 and in EP-A 485,028, this is accomplished when the health care worker advances the cartridge through the holder by rotating a clamping element.
Many holders, including the above-referenced reusable holders, enable the user to avoid handling the cartridge-needle unit when the needle unit is exposed. Nevertheless, health care workers are especially susceptible to accidental and potentially infectious, and indeed, on occasion, possibly fatal, needle strikes due to the careless handling and/or disposing of the cartridge-needle unit after use. The consequences to health care workers of strikes from needles contaminated with various infectious diseases such as hepatitis or AIDS can be particularly severe. The frequency of such accidental needle strikes in the United States is surprisingly great, and has been estimated to be approximately one million strikes per year. Moreover, the cost to health care organizations for the testing of health care workers accidentally stricken by used needles is a significant burden on health care costs. Therefore, it would be desirable to further protect health care workers by providing systems which reduce the possibility of accidental needle strikes.
To this end, it has been suggested to provide a hollow body to house the cartridge-needle unit, such that the needle can be exposed for use and then withdrawn into the body for safety. For example, WO 93/02728 describes disposable, i.e., single use, holders which can be used in conjunction with cartridge-needle units. However, this system comprises a body featuring one or more radially inwardly extending spring fingers near the plunger end of the body which engage the hub of the needle assembly and keep the needle assembly from being withdrawn from the body section. Such spring fingers are difficult to mold and require a folding step during assembly. Additionally, when folded into position, the spring fingers create an abrupt ledge which, if contacted by the cartridge-needle unit during the assembly process, can cause premature activation of the assembled unit, thus rendering the unit defective. WO 93/05834 describes another such system featuring a holder containing a radially deformable body having an elliptical cross-section. However, full elliptically shaped holders tend to inadequately support the cartridge-needle unit and cause alignment problems during manufacture and/or assembly and safety problems during use. To reduce such problems WO 93/05834 proposes the use of spring fingers, but such designs suffer from the problems discussed above. Further, holders featuring deformable bodies require that the users place their fingers close to an exposed needle with no protection during deformation. Consequently, these systems are less than fully satisfactory from a commercial standpoint.
In addition, existing safety syringe systems often are not economical to manufacture and/or assemble in large quantities. This is especially true when the syringe system is intended to be disposable.
It would be desirable to provide a holder for use with a cartridge-needle unit which enables the unit to be assembled and used safely and easily and which reduces the susceptibility of health care workers to accidental needle strikes.